Removal of organic peroxides from unsaturated hydrocarbons



l methyl-fi cyclopentene, cyclohexene, etc.

Unit d States Patemfofci REMOVAL OFORGANIC ,PEROXIDE-s FROM I UNSATURATED HYDROCARBONS V .leronie A; Vesely, Park Ridge, and Carl B. Linn, Riverside, Illa, assignors to Universal Oil Products Company,

Des Plaines, 111., a corporation of Delaware Nd Drawing. Application June 28, 1956, Serial No. 594,395

I c aims. (or. 196-44) This invention relates to a process for the removal of organic peroxides from unsaturated hydrocarbons, and more particularly, relates to a process for the removal "of organic peroxides 'from unsaturated hydrocarbons which have deteriorated during storage due to oxidation, and still more particularly relates to a process for the 'removal of'organic'peroxides from unsaturated hydro.-

carbons which comprises contacting the same with a gasolines, such changes not only decrease thesales value of the gasoline but'al so deleteriously affect its performance in internal combustion engines by clogging up feed lines, piston rings, valves, etc- Unsaturated hydrocarbons susceptible to peroxidation include olefi'hic hydrocarbons such as ethylene, propylene,

l-butene, Z-butene, isobutylene, amylenes, hexenes, heptenes, octenes, nonenes, decenes, etc., including the various isomeric forms The higher molecular weight olefins include straight-chain and cyclo-olefins, for example,

l-hexene, 2-hexene, 3 hexene, 2 methyl 1 pentene, Z-methyl 2 pentene, 2-methyl 3 pentene, 2-methyl-4- pentene, Z-methyl-l-pentene, 3-methyl-2-pentene, etc., 1 methyl 1 cyclopentene, 1 methyl 2 cyelopentene, In addition to the above-mentioned mono-olefinic unsaturated hydrocarbons, the various diolefinic hydrocarbons are also susceptible to peroxidation and are thus included within the generally broad scope of the process of -the present invention. At a matter of fact, certain diolefinic hydrocarbons, namely, conjugated diolefinic hydrocarbons, are

much more susceptible to peroxidationreactions than are mono-olefin'ic hydrocarbons. Such diolefinic hydrocarbon'slinclude butadiene, isoprene, 2,3-dimethyl-1,3- butadiene, etc. and unsaturated terpenic hydrocarbons including those containing one or more double bonds,

such as pinene, limene, dipentene, ocimene, myrcene, terpene, carenene, camphene, etc. In addition to the above-mentioned unsaturated hydrocarbons, certain alkenyl aromatic hydrocarbons are particularly subject to peroxidation reactions and thus are included within the generally broad scope of the present invention. Examples of such compounds include styrene, alpha-methylstyrene, divinyl benzene, etc; j As is readily apparent from the above described un saturated hydrocarbons susceptible to oxidation with the resultant formation of peroxides, the present invention is 2,809,921 Patented Oct. 15, 1957 applicable to a wide variety of chemical compounds alone or in admixture. Furthermore, removal of peroxides is often desirable from thermally or catalytically cracked products from the refining of petroleum such as therinally cracked gasoline, thermally cracked naphtha, catalytically cracked gasoline, catalytic'ally cracked naphtha, etc. Of course these cracked hydrocarbonaceous products from the refining of petroleum contain mixtures of many of the above-mentioned unsaturated compounds in admixture withvarious. quantities of paratfinic, naphthenic,, and aromatic compounds. The removal of peroxides from theseand .from other unsaturated organic compounds can be readilyaccompilshed by the utilization of the process of the present invention.

One embodiment of this invention relates to a process for the removal of organic peroxides from unsaturated hydrocarbons containing the same which comprises contacting said unsaturated. hydrocarbons with a hydrated complex ofa boron halide and an iron group metal halide, the metal in said metal halide being character ized by being in the valence state of 2, and withdrawing the thus contacted unsaturated hydrocarbons of substantially lower peroxide content. Another embodiment of the present invention relates to a process for the removal of organic peroxides from unsaturated hydrocarbons containing the same which comprises contacting said unsaturated hydrocarbons with a hydrated complex of boron trifluoride and ferrous fluoride, and withdrawing the thus contacted unsaturated hydrocarbons of substantially lower peroxide content. Another embodiment of thepresent invention relates to a process for the removal of organic peroxides from unsaturated hydrocarbon containing .the same which comprises contacting said unsaturated hydrocarbons with a hydrated complex of a boron halide and an iron group metal halide, the metalin said metal halide being characterized by being in the valence state of 2, withdrawing the thus contacted unsaturated hydrocarbons of substantially lowered peroxide content, stopping further contact of said unsaturatedhydrocarbons containing organic peroxides withthe complex which has become spent in its ability to move organic peroxides, thereafter treating said spent complex with a paraffinic hydrocarbon, stopping said. treating and desiceating the complex, and again contacting the regenerated complex with additional unsaturated hydrocarbons containing organic peroxides. i

A' more specific embodiment of the present invention relatesto a process for the removal of organic peroxides from unsaturated hydrocarbons containing the same which comprises contacting said unsaturated hydrocarbons with a hydrated complex of boron trifluoride and ferrous fluoride, withdrawing the thus contacted unsaturated hydrocarbons of, substantially lowered peroxide content, stopping further contacting of said unsaturated hydrocarbons containing organic peroxides with the complex which has become spent in its ability to remove organic peroxides, thereafter treating said spent complex with n-pentane, stopping said treating and desiccating the complex, and again contacting the regenerated complex with additional unsaturated hydrocarbons containing organic peroxides. i i

As set forth hereinabove, the process of the present invention is applicable to the removal of organic peroxides from diverse unsaturated hydrocarbons. Further-' suitable iron group metal halide. The boron halide may be selected from boron trifluoride, boron trichloride,"

boron tribromide and boron triiodide. In a preferred embodiment of the present invention, boron trifluoride is utilized as one of the complex constituents.- The. iron group metal halides utilized in preparing the complex are selected from ferrous, nickelous and cobaltous halides. Examples of such halides include ferrous chloride, ferrous bromide, ferrous fluoride, ferrous iodide, nickelous fluoride, nickelous chloride, nickelous bromide, nickelous iodide, cobaltous fluoride, cobaltous chloride, 'cobaltous bromide and cobaltous iodide. Of these iron group metal halides in which the metal is in the valence state of 2, ferrous fluoride is particularly preferred. Also, in the preferred embodiment of the present invention the halogen atoms in the boron halide and the halogen atoms in the iron group metal halide are the same. Thus, preferred complexes comprise the complex of boron trifluoride and ferrous fluoride, the complex of boron trifluoride and nickelous fluoride, and the complex of boron trifluoride, and cobaltous fluoride. Of these preferred complexes, the complex of boron trifluoride and ferrous fluoride are particularly preferred as stated hereinabove.

These complexes may be prepared in any suitable manner. In one method, hydrogen fluoride is reacted with iron to form ferrous fluoride and the latter is then reacted with boron trifluoride to form the complex. In another method, hydrogen fluoride and boron trifluoride are contacted simultaneously with iron. In preparing the complex, it apparently is necessary that an environment of hydrogen fluoride be present during the addition of boron trifluoride. Thus, when the hydrogen fluoride is added first and then the boron trifluoride, sufficicnt hydrogen fluoride should be present in the system in order to effect the formation of the desired complex. The iron preferably is in a finely divided state and conveniently comprises iron powder. The reaction is exothermic and yields one mol of hydrogen for each gram atom of hydrogen. It will be noted that the preferred reaction involves two mols of hydrogen fluoride and one mol each of iron and boron trifluoride.

The complexes formed as described hereinabove are then hydrated in any suitable manner. In one method, the complex is dissolved in sufficient water to insure complete solution, and the water is then allowed to evaporate. The evaporation may of course be speeded up by the application of heat or the application of vacuum or a combination of both. In any case, however, the application of heat must be limited so that the temperature of the hydrated complex does not exceed about 150 C. since above that temperature BFa may be evolved.

The hydrated complex as formed hereinabove is then utilized for the removal of peroxides from unsaturated hydrocarbon containing the same. Since the hydrated complexes are solids, the contacting of the same with peroxidized unsaturated hydrocarbons can be accomplished in batch type or continuous process. In a simple batch type operation, a sufficient quantity of the hydrated complex is added to a quantity of the peroxidized unsaturated hydrocarbon and the mixture is then stirred or contacted in any suitable manner. After a suflicient period of time has elapsed, the thus contacted hydrocarbons are separated from the hydrated complex and they are found to have a substantially lower peroxide content. In another method of operation, the hydrated complex may be placed as a fixed bed in a treating zone and the peroxidized unsaturated hydrocarbons passed therethrough continuously. Furthermore, if economics so dictate, the hydrated complex may be used as a moving bed, fluidized fixed bed, or in a fluidized process. In any case, however, suflicient pressure will be maintained upon the treating zone so that the unsaturated hydrocarbons are maintained in liquid state.

While the operating conditions selected for the treating step in the processcf the present invention may vary over a wide range, the temperature will usually range from about -50 to about C., the pressure will range from about 0 to about 500 p. s. i. g., and the hourly liquid space velocity will range from about 0.5 to about 50 or more. In a batch type process, the hydrated complex will normally be utilized in an amount of from about 0.1 to about 10 percent by weight of the unsaturated hydrocarbons to be treated. When it is desired to utilize higher temperatures, the pressure will be raised not only to maintain the unsaturated hydrocarbons in liquid form but also to preclude loss of water and boron trifluoride which will result in dissociation of the complex.

The exact mechanism by which the peroxides are removed from the unsaturated hydrocarbons by contacting the same with the hydrated complex of a boron halide and iron group metal halide is not known. However, it has been found that the hydrated complexes tend to become spent after the passage of large quantities of peroxidized unsaturated hydrocarbons thereover. As an additional feature of the process of the present invention, it has been found that when the hydrated complexes become spent, they can be reactivated by treatment with paraffinic hydrocarbons followed by drying or desiccation. When the unsaturated hydrocarbons containing organic peroxides comprise cracked gasolines, such cracked gasolines apparently contain suflicient quantities of paraffinic hydrocarbons so that the process of the present invention can be carried on for very long periods of time without the necessity for reactivation of the hydrated complex. However, when the substantially pure unsaturated hydrocarbons containing peroxides are contacted with the hydrated complex, it has been found necessary to reactivate the complex at frequent intervals, these intervals being determined by the point when the unsaturated hydrocarbon products of the process do not show a substantial reduction in peroxide content. This reactivation as hereinabove set forth is accomplished by contacting the spent hydrated complex with a paraflinic hydrocarbon. The paraflinic hydrocarbon to be utilized will be one which is normally liquid and free from peroxides. Such parafiinic hydrocarbons include n-pentane, Z-methyl pentane, neopentane,'n-hexane, 2-methyl pentane, B-methyl pentane, 2,2-dimethyl butane, n-heptane, 2-methyl hexane, 3- methyl hexane, n-octane, etc., and naphthenic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, etc. .Such paraflinic hydrocarbons may be used alone or in admixture with one another and substantially saturated gasoline .or naphtha fractions may also be utilized including straight run gasoline, natural gasoline, straight run naphtha, Fischer-Tropsch gasoline, etc. Such naturally occurring gasoline or naphtha fractions contain little or no unsaturated hydrocarbons in the chemical sense although they may contain very substantial quantities of aromatic hydrocarbons, the presence of which is not detrimental to the-reactivation step. Also, specially treated gasolines or naphthas such as Stoddards solvent and ,various acid treated hydrocarbon fractions containing substantially no aromatics or unsaturated hydrocarbons may also be utilized. In any case, it should be obvious that the selection of desired reactivation agent may be made from the rather general and broad category of saturated hydrocarbons.

The process of this invention is further illustrated by the following examples from which no intention to unduly limit the generally broad scope of this invention is to be inferred.

Example I This example illustrates the removal of organic peroxides from unsaturated hydrocarbons containing the same by contacting with a hydrated complex of boron trifluoride and ferrous fluoride. The complex of boron trifluoride and ferrous fluoride was prepared first by charging 26 grams of ironpowder into a copper liner of an 850 cc.

rotating autoclave. The autoclave was closed, evacuated, and cooled, and 73 grams of liquid anhydrous hydrogen fluoride was added thereto. Then, 47 grams of boron trifluoride was pressured into the autoclave resulting in a pressure of 360 p. s. i. g. The autoclave was rotated for 2 hours time at 25 C. during which time the pressure dropped from 360 p. s. i. g. to 280 p. s. i. g. followed by a slight increase to 286 p. s. i. g At the end of the 2 hour period, the pressure on the autoclave was discharged and the hydrogen fluoride removed therefrom by slightly heating the autoclave After opening the auto clave, 62 grams of a nearly white solid was recovered therefrom. Analysis of the solid was very close for that indicated by the formula FeFz-BFa.

12.0 grams of FeF2-BFa was placed in a desiccator over a saturated barium chloride solution and in 48 hours time absorbed 8.3 grams of water. This amount of water is equivalent to a molar ratio of 6:1, thus giving FeFz BFa 6H2O This product was desiccated at room temperature in vacuum over calcium chloride for 71 hours during which time it lost 3.4 grams of water to give a composition equivalent to FeFz BFa 3.6Hz0.

A sample of the FeF2-BF3-3.6H2O was contacted with methylcyclohexene which had been found to contain peroxides by the ferrous sulfate test. After treating with FeF2-BF3-3.6H2O, the methylcyclohexene gave negative results with ferrous sulfate. It should be mentioned that a temperature effect was noted upon contacting the peroxidized methylcyclohexene with the hydrated complex. A sample of methylcyclohexene which had been purified to remove peroxides showed no temperature efiect with the hydrated complex.

After separating the treated methylcyclohexene from the hydrated complex, it was noted that the complex became sludgy. This recovered complex was rinsed with n-pentane and desiccated in vacuum over calcium chloride at room temperature. The resultant solid hydrated complex was subsequently utilized for the removal of additional peroxides from peroxidized methylcyclohexene. This procedure was successfully repeated several times.

Example 11 This example illustrates the removal of organic peroxides from a thermally cracked gasoline containing the same by contacting with a hydrated complex of boron trifluoride and cobaltous fluoride. A complex of boron trifluoride and cobaltous fluoride is prepared in substantially thesame manner as described hereinabove for the preparation of the complex of boron trifluoride and ferrous fluoride. 91 g. of hydrogen fluoride were placed in the autoclave which was then heated for one hour at 100 C. After cooling to room temperature, the pressure was 100 p. s. i. g., indicating reaction had occurred. This pressure was released and the gas measured indicating the product of 0.2 mol of hydrogen. Then 39 g. of boron trifluoride was pressured into the autoclave resulting in a pressure of 220 p. s. i. g. which pressure dropped off to 100 p. s. i. g. during 2 hours rotation at 23 C. On opening the autoclave, 54 g. of a lavender solid was recovered.

18 g. of the lavender solid was dissolved in boiling water, the solution filtered, and the filtrate evaporated to dryness. The hydrate was recovered in the quantity of 20.1 g. and was a pink crystalline solid, the crystals being in the form of flat prisms. From a consideration of the analyses of this hydrate and also from theoretical considerations, the hydrated complex has been assigned the formula of COFa-l/SBFa-HaO.

Five grams of this complex is placed as a fixed bed in a small glass tube and peroxidized thermally cracked In this case, 29.5 g. of cobalt powder and gasoline passed therethrough at a liquid hourly space velocity of 1, at room temperature, and at atmospheric pressure. The eflluent gasoline is found to be free from peroxides by the ferrous sulfate test. When peroxides begin to appear in the effiuent, this hydrated complex can be reactivated by treatment with n-hexane, and reused in the process.

Example III This example illustrates a process for the removal of organic peroxides from a catalytically cracked naphtha. A sample of the naphthais contacted with the hydrated complex of boron trifluoride and ferrous fluoride as described hereinabove in Example I. The naphtha after treatment gives a negative result when tested for peroxides by the ferrous sulfate test.

We claim as our invention:

1. A process for the removal of organic peroxides from unsaturated hydrocarbons containing the same which comprises contacting said unsaturated hydrocarbons with a hydrated complex of a boron halide and an iron group metal halide, the metal in said metal halide being characterized by being in the valence state of two, and withdrawing the thus contracted unsaturated hydrocarbons of substantially lowered peroxide content.

2. The process of claim 1 further characterized in that the boron halide is boron trifluoride and the iron group metal halide is ferrous fluoride.

3. The process of claim 1 further characterized in that the boron halide is boron trifluoride and the iron group metal halide is nickelous fluoride.

4. The process of claim 1 further characterized in that the boron halide is boron trifluoride and the iron group metal halide is cobaltous fluoride.

5. The process of claim 1 further characterized in that the hydrated complex of a boron halide and an iron group metal halide is FeFz-BFr (H2O)3.o.

6. A process for the removal of organic peroxides from unsaturated hydrocarbons containing the same which comprises contacting said unsaturated hydrocarbons with a hydrated complex of a boron halide and an iron group metal halide, the metal in said metal halide being characterized by being in the valence state of two, withdrawing the thus contacted unsaturated hydrocarbons of substantially lowered peroxide content, stopping further contacting of said unsaturated hydrocarbons containing organic peroxides with the complex which has become spent in its ability to remove organic peroxides, thereafter treating said spent complex with a paraflinio hydrocarbon, stopping said treating and desiccating the complex, and again contacting the regenerated complex with additional unsaturated hydrocarbons containing organic peroxides.

7. The process of claim 6 further characterized in that the boron halide is boron trifluoride and the iron group metal halide is ferrous fluoride.

8. The process of claim 6 further characterized in that the iron group metal halide is nickelous fluoride.

9. The process of claim 6 further characterized in that the boron halide is boron trifluoride and the iron group meal halide is cobaltous fluoride.

10. The process of claim 6 further characterized in that the hydrated complex of boron halide and iron group metal halide is FeFz-BFz- (H20)3.6 and the paraflinic hydrocarbon is n-pentane.

References Cited in the file of this patent UNITED STATES PATENTS 2,416,465 Axe Feb. 25, 1947 2,563,598 Fuqua Aug. 7, 1951 2,647,858 Weisz Aug. 4, 1953 2,704,738 Simpson Mar. 22, 1955 2,745,792 Shiah May 15, 1956 

1. A PROCESS FOR THE REMOVAL OF ORGANIC PEROXIDES FROM UNSATURATED BYDROCARBONS CONTAINING THE SAME WHICH COMPRISES CONTACTING SAID UNSATURATED HYDROCARBONS WITH A HYDRATED COMPLEX OF A BORON HALIDE AND AN IRON GROUP METAL HALIDE, THE METAL IN SAID METAL HALIDE BEING CHARACTERIZED BY BEING IN THE VALENCE STATE OF TWO, AND WITHDRAWING THE THUS CONTRACTED UNSATURATED HYDROCARBONS OF SUBSTANTIALLY LOWERED PEROXIDE CONTENT. 